Cancer is distinguished by uncontrolled proliferation of cells. The cellular components of blood originate from pluripotent hematopoietic stem cells. Via their regenerative and differentiating capacities, stem cells generate lymphoid and myeloid precursors, which then produce lymphocytes, neutrophils, eosinophils, basophils, erythrocytes, and platelets. In leukemia, high levels of immature white blood cells, or blasts, are present. Four main types of leukemia are recognized: acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL) and chronic myeloid leukemia (CML); although less common types are known as well.
Leukemia has an average 5-year mortality rate of 40%, and in 2012 developed in over 350,000 people globally. Therefore, there remains a continued and urgent need for therapies directed toward treatment of leukemia.